Surface and bulk ultra-short pulsed laser processing of transparent materials

Ingolf V. Hertel, Razvan Stoian, David Ashkenasi, Arkadi Rosenfeld, Eleanor E.B. Campbell

Research output: Contribution to journalConference articlepeer-review

9 Scopus citations


Ultrashort pulsed laser ablation of dielectrics has been investigated using ex-situ morphological examinations in combination with in-situ time-of-flight mass spectrometry of the ablated species. Analysis of the energy spectrum of the ablation products provides a wealth of information on the processes occurring during femtosecond laser ablation of materials. The presentation will focus on the case of sapphire (Al2O3) and discuss the fundamental processes in ultrashort pulsed laser sputtering. Two different ablation phases have been identified, a `gentle' phase with low ablation rates and a `strong' etch phase with higher ablation rates, but with limitation in structure quality. A comparison of the energy and momentum distributions of ejected ions, neutrals and electrons allows one to distinguish between non-thermal and thermal processes that lead to the macroscopic material removal. Fast positive ions with equal momenta are resulting from Coulomb explosion of the upper layers at low fluence and low number of irradiating laser pulses (`gentle' etch phase). Pump-probe studies with fs laser pulses reveal the dynamics of excitation and electron mediated energy transfer to the lattice. At higher laser fluences or after longer incubation, evidence for phase explosion can be derived from both the morphology of the surface and the results of the in-situ experiments.

Original languageEnglish
Pages (from-to)17-24
Number of pages8
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - 2000
Event1st International Symposium on Laser Precision Microfabrication - Omiya, Jpn
Duration: 14 Jun 200016 Jun 2000


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